This invention relates to a dust cover for sealing a space between a body member and a shaft slidably received in the body member to protect the space against the ingress of dust, water or the like.
Usually, the dust cover is formed of a flexible material such as rubber or the like, with one end portion thereof fittingly and sealingly surrounding a portion of the shaft projecting out of the body member, and the other end portion thereof being secured to the body member. The intermediate portion connecting the opposite end portions covers the space between the shaft and the body member thereby blocking the ingress of dust or the like. The relative movement between the shaft and the body member is accomodated by the intermediate portion which has a small thickness and a sufficient flexibility.
However, there are shortcomings in conventional dust covers, such that the sealing function is solely accomplished by the small thickness portion and thus the sealing function will be decreased when the small thickness portion is aged or damaged, and that in mounting the dust cover the small thickness portion, particularly, the portion adjacent to the end portion secured to the body member will sometimes be displaced radially inwardly to contact the circumference of the shaft and, thus, be carried into the bore of the body member and clamped between the shaft and the body member when fitting the shaft into the bore, and damaged accordingly.